Wingsail detail

Nailing down the details, from scantlings to stay angles, foil design, deck hardware, and all the other details.
User avatar
Skip
Posts: 236
Joined: 31 Aug 2014, 16:40

Wingsail detail

Postby Skip » 24 Feb 2015, 21:52

At almost the eleventh hour a new thought hit while contemplating using Nomad.
With the counterbalanced wingsail I don't see much penalty in tilting sail axis inward current thought is about parallel to deck (~ 4 degrees) would make control mechanism a bit cleaner, move weight inboard lift the bow just a smidgen and depress the stern.

Any thoughts?
Skip

NomadE3b.jpg
User avatar
Manik
Site Admin
Posts: 359
Joined: 27 Aug 2014, 15:41
Location: Braunschweig, Germany
Contact:

Re: Wingsail detail

Postby Manik » 26 Feb 2015, 08:30

I don't know what your control mechanism looks like, but the wingsails may swivel in ghosting conditions, with the tilted setup. How does it simplify the control mechanism? (And where can I see the control mechanism? :D )

Cheers,
Marco
"Man's mind and spirit grow with the space in which they are allowed to operate." - Krafft A. Ehricke, rocket pioneer
User avatar
Skip
Posts: 236
Joined: 31 Aug 2014, 16:40

Re: Wingsail detail

Postby Skip » 26 Feb 2015, 15:51

Manik wrote:I don't know what your control mechanism looks like, but the wingsails may swivel in ghosting conditions, with the tilted setup. How does it simplify the control mechanism? (And where can I see the control mechanism? :D )

Cheers,
Marco


The wings will be mass balanced around the pivot axis, one of the lessons learned from BB. The control mechanism consist of a circular cam concentric with the pivot axis that slides fore and aft on the hull. Cam follower is pivoted on the wing which can rotate thru 360d. The cam concept is from Peter Worsely in England (patented there), he's got some info on website, was a little hard for me to grasp at first but it's a natural for proas.

Since everything is parallel and perpendicular to the pivot axis it's just a little neater to have stuff lined up on same.

Picturewise there's one buried in this forum :)
download/file.php?id=160&mode=view

Best overall pictures that I know of are on Jim Michalak's website about two thirds the way down thru the pictures of SailOK 2014.
http://www.jimsboats.com/15oct14.htm

Cheers,
Skip
User avatar
Rob Zabukovec
Posts: 509
Joined: 27 Aug 2014, 21:20
Location: Southern Tasmania Australia

Re: Wingsail detail

Postby Rob Zabukovec » 27 Feb 2015, 22:01

Skip,

I am no expert, but by canting the wingsails fore and aft as you have suggested, it seems to me that the aft wingsail in will be less stable rotationally and the fore wingsail will be harder to rotate than a vertical one, especially in a seaway????

RobZ
User avatar
Manik
Site Admin
Posts: 359
Joined: 27 Aug 2014, 15:41
Location: Braunschweig, Germany
Contact:

Re: Wingsail detail

Postby Manik » 27 Feb 2015, 22:50

I don't follow your thinking Rob, how so? :|
"Man's mind and spirit grow with the space in which they are allowed to operate." - Krafft A. Ehricke, rocket pioneer
User avatar
Skip
Posts: 236
Joined: 31 Aug 2014, 16:40

Re: Wingsail detail

Postby Skip » 28 Feb 2015, 02:37

Rob Zabukovec wrote:Skip,

I am no expert, but by canting the wingsails fore and aft as you have suggested, it seems to me that the aft wingsail in will be less stable rotationally and the fore wingsail will be harder to rotate than a vertical one, especially in a seaway????

RobZ


Hi Rob,

Experts on boat wingsails pretty hard to come by :) With BB there were a lot of handling issues at first that went away as the wing was counter weighted. BB's wingsail was canted to windward about 5 degrees, a combination of overweight live load (me) and a slightly undersized float based on the chunk of foam I had at hand.

I based a lot of my early thinking and expectations on the experiences of land sailors. One, the idea that mass (counter) balancing wasn't all that important turned out not to apply to waterborne craft. From the standpoint of oscillation, acceleration and light conditions mass balancing is essential in our venue.

Another idea from the land borne that does have some merit is that if there is enough wind to rotate the wing, even if it's light, it is enough to operate. Otherwise it's auxiliary power time.

Now that I've had some time to think on it Nomad will probably have wingsail axis perpendicular to the local deck (2d +/- off vertical). For some reason the plumb straight up and down parallel wings offends my sensibilities a bit.

Cheers,
Skip
User avatar
Rob Zabukovec
Posts: 509
Joined: 27 Aug 2014, 21:20
Location: Southern Tasmania Australia

Re: Wingsail detail

Postby Rob Zabukovec » 28 Feb 2015, 02:53

@Skip,

I have no problems with and fully understand the counterbalance issue. I also appreciate aesthetic sensibilities, we both earned our living over (too??) many years doing the same trade......but I have to say as a gut reaction, I think the reverse. It just looks wrong to me. And I am pretty sure that the two wings will behave differently. Which may or may not be a bad thing.

In any case, I would also arrange the deck lines and the bottom of the rigs to be sufficiently in plane and close at all angles to achieve a truly effective end plate effect. Look at Fran Cammas' C class cat Groupama.

PS: If I were going down the solid winged schooner route and was sufficiently concerned over the aesthetics, I would look at cranked pivots making both wings aft raked. No counterbalance variations....and much easier on the eye..... Then flatten the decks and sheerline for endplate effect.

@ Marco,

I think it is because of the height differential between the wing CG (higher and in Nomad's case ~ double) and the counterbalance CG????

1) Straight fore and aft (@0 degrees), if the rig is "balanced" on the aft (forward raked) rig then on the forward (aft raked) rig the wing moment will be greater than the counterbalance moment providing additional resistance to rotation.

2) Rigs eased, at some point towards 90 degrees, the aft (forward raked rig) wing CG will be further away than the counterbalance CG from the deck pivot so the wing moment will be greater than the counterbalance moment, making it unstable (ie wanting to shunt). On the forward (aft raked rig) the same thing happens, but in this case it adds to the moment wanting to return the wing to fore and aft (@ 0 degrees) thereby providing still more resistance to rotation.

Small numbers but possibly significant. Something to watch out for????

Cheers

RobZ
User avatar
Skip
Posts: 236
Joined: 31 Aug 2014, 16:40

Re: Wingsail detail

Postby Skip » 01 Mar 2015, 19:40

Rob,

I appreciate the comments and yes it was a number of years, enjoyed it and would still be doing it but the combination of more regulation and slower mental agility made it easy to hang it up at the end of 2014. So it's more boat time, if it ever warms up :roll:

The sensibilities bothered by the wingsail detail more technical than aesthetic. Form follows function in this case since that's the most probable path to the lightest least stressed craft I'm capable of. The cranked pivot reminds me of a segment on TV last night on the helicopter that can fly inverted. The rotor head is CNC machined from a solid (large) block of titanium. Were it me I'd stay upright but admire those that do really push the envelope.

In my case it's not pushing the envelope but seeking the easiest simplest way to travel the path I'm on. Nomad won't have any control lines as such, the wings feather into the wind where ever it comes from and then develops thrust depending on the cam setting. I'm still trying to grasp all the ramifications, BB was successful enough that I sold it to a friend to play with while I devote the time to make Nomad a reality.

Here's a couple of slightly more accurate views of the boat with vertical wings and tilted 2 degrees, along with a couple of pictures of the rather crude model of the boat with similar orientations.

Cheers,
Skip

twodegree.bmp.jpg
Two Degrees
Vertical.jpg
Vertical

twodegrees.JPG
Vertical.JPG
User avatar
Rob Zabukovec
Posts: 509
Joined: 27 Aug 2014, 21:20
Location: Southern Tasmania Australia

Re: Wingsail detail

Postby Rob Zabukovec » 01 Mar 2015, 22:11

Skip,

I retired pretty much for the same reasons. I still prefer the vertical option, aesthetically and technically.

I wish you well with it.

RobZ
User avatar
Amati
Posts: 186
Joined: 06 Nov 2014, 02:16

Re: Wingsail detail

Postby Amati » 05 Mar 2015, 01:34


Return to “3. Detailed Design”

Who is online

Users browsing this forum: No registered users and 0 guests